Nutrients And Water Transport

Front 1

Need for Growth

Back 1

About 95% of herbaceous plants is water; it takes up a lot of space

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Water is needed for

Back 2

most chemical reactions to occur.

Turgor pressure

Front 3

Transpiration

Back 3

the evaporation of water from plant surfaces (mostly stomates). 98% of absorbed water is lost by transpiration

Front 4

transpiration stream

Back 4

upward movement of water

Carries nutrients and in at least some plants carries amino acids made in roots to rest of plant.

Cools plant somewhat.

Front 5

hygroscopic movements

Back 5

grass seeds even have an awn which expands and contracts in response to RH; this tells seed where and how to germinate (since high RH indicates water is present nearby)

Front 6

Path of H2O

Back 6

Water always osmoses from areas of lower solute concentration to areas of higher solute concentration.

Usually, the soluble salts in soils slow or prevent this.

Once in the xylem, water moves upward or sideways rapidly; an organ, it again osmoses from cell to cell. In epidermis, may then exit via stomates. So, water tends to move to fast growing or transpiring plant parts; they need it and it moves to them because they contain concentrated solutes.

Front 7

adhesion

cohesion

Back 7

In the xylem, water molecules adhere to the walls of the conducting cells in this process (like water sticks to the sides of a straw).

Then other water molecules stick to the first in a process termed (that's how liquids fill in the center of a straw).

Front 8

Narrow vessels and tracheids

Back 8

help reduce pull needed to move water upward without "breaking" the column of water. Also, better to have lots of narrow vessels and tracheids rather than a few fat ones in case cavitation

Front 9

cavitation

Back 9

this is when bubbles form due to inconsistent transpiration rate, then the bubbles block further conduction in that tube for the rest of the day

Front 10

root pressure

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because the absorbed water has to go somewhere, so it "pushes" upward into the xylem.

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guttate

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or exude excess water through special openings in their margins called hydathodes

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Inherited adaptations

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Plants may cope with water stress by:

These are xerophytes (they are xerophytic).

Some are also halophytes, plants adapted to salty soils.

Small or no leaves.

*Sunken stomates.

Wax

*Hairs/spines to shade and hold air.

*Succulent stem and/or leaves.

*Deep roots or very widespread shallow roots (genetic control)

*Avoid dry times by developing before drought occurs.

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Individual adaptations

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Roots "seek" water they grow toward it.

*Produce more wax, smaller leaves, fewer fruits.

*Close stomates.

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People try to help by

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Watering; Applying antitranspirants (may result in less wax produced, so blue spruce looks green); Watergrabber et al

Front 15

Symptoms of < water:

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Drop nonessential parts leaves, flowers, fruits.

Leaves and herbaceous stem wilt due to lost turgor pressure. eLeaf tips and margins turn crisp brown; they are the last part to get water, so the first to dry out.

Early fall color.
Roots become crisp.

Growth, both above and below ground, slows. Death.

Internally, < water causes plasmolysis

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plasmolysis

Back 16

Water osmoses out of cells, the protoplasts pull away from the walls and the vacuoles shrink. Think of a water balloon in a box; if the balloon is full, it presses the sides of the box; if the balloon leaks, it shrinks and no longer touches the box. If plasmolysis is prolonged, the cell dies, but if corrected quickly, the protoplast fills again and the cell lives.

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Symptoms of > water:

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Drop nonessential parts. Plant wilts.

Leaves are soft and brown (often reddish brown in evergreens) or turn red early on some deciduous plants.

Growth slows.

Roots mushy, often smelly. Death.

Notice: many symptoms same as for insufficient water; best to tell apart by studying water's habits and/or looking at the roots.

Front 18

Most plants absorb water through their roots:

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Stomata let water vapor escape, not take it in; besides, their main function is to allow C02 to enter.

C02 is about 0.03% of our air; it is concentrated greatly upon entering the plant.

Front 19

C02 gradient

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which is steepest when photosynthetic cells directly contact air. Hence lots of air spaces in mesophyll. And having flat leaves helps since most cells are near a stomate or air pocket

Front 20

autotrophic

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CO2 is needed as the base for all organic compounds, allowing plants to function this way

Front 21

Oxygen

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Oxygen is absorbed as 02 from the air, especially from soil air, by the roots. It is also absorbed by leaves at night, broken from water in Ps or absorbed dissolved in water.

Front 22

waterlogged soil

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bad it reduces the amount of molecular oxygen available to plant roots, making the plant work harder to get the same amount of 02 (It also encourages many diseases.)

Front 23

O2 is required

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Oxygen is required for respiration, the "burning" of organic compounds to release energy.

Front 24

Homeostasis

Back 24

is a condition of dynamic equilibrium in living systems like plants. It means the balance between diffusion, osmosis, imbibition, transpiration and guttation is constantly adjusted.

Front 25

stomata and hydrathodes

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Roots absorb water, much of which is lost through the stomata, which simultaneously allow entrance of C02 Some water drips out of hydathodes, while cuticle blocks water loss.

Front 26

turgid reaction

Back 26

Stomata open when guard cells are turgid. Guard Cells become turgid as solute concentrations increase; these are increased by an influx of K ions or by starch breaking down into more (though smaller) sugar molecules. The reverse occurs to encourage water to osmose out K leaves the cell and sugars combine to form starches.

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Elements for plant nutrients

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Basic - C, H, O

Primary - N, P, K, Fe

Secondary - S, Ca, Mg, B, Mo, Cu, Zn, Mn, Cl

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Macro-nutrient

Micro-nutrient

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essential element needed in large quantities

trace element; needed in tiny amounts

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Mobile element

Immobile element

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nutrient that is translocated to young growth if a deficiency occurs (1st appear in old growth)

nutrient that is not translocated to young growth if deficency occurs (1st appear in young growth)